Hybrid microlens-polymer dispersed liquid crystal substrate for synergistic light extraction from flexible OLEDs

This study proposes a novel hybrid substrate that integrates a microlens array (MLA) with a polymer dispersed liquid crystal (PDLC) to enhance external light extraction efficiency in flexible organic light emitting diodes (OLEDs). The proposed MLA imprinted PDLC (MIP) substrate significantly improves light extraction by synergistically combining the strong volumetric scattering of the PDLC with the interfacial refraction of the MLA. Simultaneously, the polymer matrix provides excellent mechanical flexibility, making the substrate well suited for flexible OLED applications. The validity of the proposed structure was verified through Monte Carlo ray-tracing simulations. When applied to flexible OLEDs, the MIP substrate exhibits a high haze of 98.5% and achieves a 21% enhancement in external quantum efficiency (EQE) compared with a reference device. The MIP is fabricated through a simple room temperature solution process involving only spin coating and UV curing. This facile method provides excellent scalability for large area applications, including roll-to-roll and printing processes. Thus, the proposed MIP platform offers a practical and effective approach for advancing next generation flexible optoelectronics.